Many polymers used in packaging materials and other articles are permeable to oxygen. When oxygen permeates a polymeric composition or article, it can cause oxidative damage. It is therefore desirable for certain polymer compositions and articles to have oxygen scavenging capability, such that when oxygen permeates the composition or article, oxidative damage can be mitigated.
It can be desirable to have a colorant in oxygen scavenging polymer compositions, such as those used for preparing articles for food and beverage packaging, among others. Oftentimes, the addition of a colorant to such a composition interferes with the oxygen scavenging properties. To overcome this problem, it is possible to reformulate the colorant such that the colorant no longer interferes, or interferes less, with the oxygen scavenging capability of the composition. However, this approach relies on an iterative process wherein a colorant is mixed with a composition, oxygen scavenging is tested, and if oxygen scavenging is unacceptable, the colorant is reformulated until a suitable composition is obtained. This process is time consuming and often results in unacceptable formulations.
Another approach involves simply using colorants that do not interfere, or interfere at an acceptable level, with the oxygen scavenging capabilities of the composition. However, this approach requires an identification of colorants that meet these criteria. This process is also time consuming and does not allow for the use of some colorants that are incompatible with composition but that may nevertheless be desirable.
Thus, there is a need for oxygen scavenging polymer compositions that are compatible with colorants, such that the addition of the colorant to the composition does not unduly interfere with the oxygen scavenging properties of the composition. These needs and other needs are satisfied by the present invention.